Back to results
US 10,892,832 B2Granted
Moving platform roll angle determination system using RF communications link
AssigneeTeledyne Scientific & Imaging, LLC
InventorsAdam Young, Bruce K. Winker
Life of this patent
Estimating the term…
Abstract
An orientation tracking system for a moving platform includes a transmitter which generates an beam having a known polarization with respect to a predefined coordinate system. The moving platform includes an ellipsometric detector capable of detecting the polarized beam when within the line-of-sight of the transmitter, and measuring its polarization state. The polarization state indicates the rotational orientation of the moving platform with respect to the predefined coordinate system. The beam could also be used to convey guidance commands to the platform.
Claims34
A moving platform orientation measurement system, comprising:
- a ground-based transmitter, comprising a dual-polarized transmitting antenna, said ground-based transmitter arranged to:
- generate two distinct, orthogonal linearly polarized radio frequency (RF) signals,
- receive said two distinct, orthogonal linearly polarized RF signals at said dual-polarized transmitting antenna;
- and to
- simultaneously radiate said two distinct, orthogonal linearly polarized radio frequency (RF) signals from said dual-polarized transmitting antenna,
- said transmitted RF signals having known but different polarizations with respect to a predefined coordinate system;
- and
- at least one moving platform, each moving platform comprising a linearly polarized receiving antenna capable of receiving said two orthogonal linearly polarized RF signals, said transmitter and receiving antenna arranged such that the roll angle of said moving platform can be determined based on the ratio of the power amplitudes of said two orthogonal linearly polarized RF signals, said roll angle θ given by tan−1(Pv/Ph) where Pv is the power amplitude of said received RF signal in the vertical direction and Ph is the power amplitude of said received RF signal in the horizontal direction;
- wherein said ground-based transmitter is arranged to encode guidance commands into said two distinct, orthogonal linearly polarized RF signals by modulating at least one of said transmitted RF signals and said moving platform is arranged to detect and decode said signals and thereby detect said guidance commands.
6 more elements
A moving platform orientation measurement system, comprising:
- a transmitter which includes a transmitting antenna and is arranged to transmit at least one radio frequency (RF) signal, each transmitted RF signal having a known polarization with respect to a predefined coordinate system and, when there are more than one transmitted RF signal, said RF signals having known but different polarizations with respect to said predefined coordinate system;
- and
- at least one moving platform, each moving platform comprising a receiving antenna capable of receiving said at least one polarized RF signal, said transmitter and receiving antenna arranged such that the roll angle of said moving platform can be determined based on said transmitted and received RF signal;
- wherein said moving platform is arranged to receive guidance commands via said received RF signals and to vary its trajectory in response to said guidance commands;
- wherein said moving platform includes a control device which affects the path of said platform when actuated and which rotates with said platform, said transmitter arranged to send guidance commands which actuate said control device such that said platform's trajectory is affected, said system arranged to detect how said platform's trajectory is affected by said actuation and to thereby determine the position of said control device at the time of said actuation;
- and
- wherein said transmitter generates two orthogonal linearly polarized RF signals and said antenna is a linearly polarized antenna which receives said two orthogonal linearly polarized RF signals, said roll angle θ given by tan−1(Pv/Ph) where Pv is the power amplitude of said received RF signal in the vertical direction and Ph is the power amplitude of said received RF signal in the horizontal direction, said system arranged to track the orientation of said control device by counting the changes in slope of said angle θ after the position of said control device at the time of said actuation has been determined.
4 more elements
A moving platform orientation measurement system, comprising:
- a transmitter which includes a transmitting antenna and is arranged to transmit at least one radio frequency (RF) signal, each transmitted RF signal having a known polarization with respect to a predefined coordinate system and, when there are more than one transmitted RF signal, said RF signals having known but different polarization with respect to said predefined coordinate system;
- and
- at least one moving platform, each moving platform comprising a receiving antenna capable of receiving said at least one polarized RF signal, said transmitter and receiving antenna arranged such that the roll angle of said moving platform can be determined based on said transmitted and received RF signal;
- wherein said moving platform is arranged to receive guidance commands via said received RF signals and to vary its trajectory in response to said guidance commands;
- wherein said moving platform includes a control device which affects the path of said platform when actuated and which rotates with said platform, said transmitter arranged to send guidance commands which actuate said control device such that said platform's trajectory is affected, said system arranged to detect how said platform's trajectory is affected by said actuation and to thereby determine the position of said control device at the time of said actuation;
- and
- wherein said transmitter generates one linearly polarized RF signal and said antenna is a dual-polarized antenna which receives said linearly polarized RF signal and produces first and second output signals P1 and P2, respectively, which represent the power amplitudes of said received linearly polarized RF signal at first and second orthogonal polarizations, respectively, said roll angle θ given by tan−1 (P1/P2), said system arranged to track the orientation of said control device by counting the changes in slope of said angle θ after the position of said control device at the time of said actuation has been determined.
4 more elements
A moving platform orientation measurement system, comprising:
- a transmitter which includes a transmitting antenna and is arranged to transmit at least one radio frequency (RF) signal, each transmitted RF signal having a known polarization with respect to a predefined coordinate system and, when there are more than one transmitted RF signal, said RF signals having known but different polarizations with respect to said predefined coordinate system;
- and
- at least one moving platform, each moving platform comprising a receiving antenna capable of receiving said at least one polarized RF signal, said transmitter and receiving antenna arranged such that the roll angle of said moving platform can be determined based on said transmitted and received RF signal;
- wherein said moving platform has an associated longitudinal axis around which it rotates, further comprising:
- an additional antenna oriented normal to said longitudinal axis;
- and
- a power detector coupled to the output of said additional antenna and arranged to detect the difference in temperature between when said additional antenna is pointing skyward and when said additional antenna is pointing toward the ground.
4 more elements
A method of determining the roll angle of a moving platform, comprising:
- receiving, at a dual-polarized transmitting antenna, two distinct orthogonal linearly polarized RF signals;
- simultaneously transmitting, from the ground, said two distinct, orthogonal linearly polarized RF signals using said dual-polarized transmitting antenna;
- polarizing each of said transmitted RF signals with respective known polarizations with respect to a predefined coordinate system;
- encoding guidance commands into said two distinct, orthogonal linearly polarized RF signals by modulating one or both of said orthogonal linearly polarized RF signals transmitted from the ground;
- receiving said transmitted orthogonal linearly polarized RF signals at said platform;
- and
- determining the roll angle of said moving platform with respect to said predefined coordinate system based on the ratio of the power amplitudes of said received orthogonal linearly polarized RF signals, said roll angle θ given by tan−1(Pv/Ph) where Pv is the power amplitude of said received RF signal in the vertical direction and Ph is the power amplitude of said received RF signal in the horizontal direction.
4 more elements
Dependencies are inferred from the claim text.